


This Is Gross: How To Respond When Your Children Ask You For A New Sibling

by acoolegg



Series: This Is Gross: The Short Story Series [2]
Category: Undertale (Video Game)
Genre: Children, Cute Kids, DIET dirty jokes for those of you that can't handle full bodied dirty jokes, Domestic Fluff, F/M, Fluff, Marriage, Other, PG, Short, Some Cursing, domestic life, sfw
Language: English
Status: Completed
Published: 2015-12-14
Updated: 2015-12-14
Packaged: 2018-05-06 17:57:17
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 1,747
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5426375
Author URL: https://archiveofourown.org/users/acoolegg/pseuds/acoolegg
Summary: <blockquote class="userstuff">
              <p>Your daughters approach you about a serious subject.<br/>(They're six and four, they can barely pee by themselves. Why are they asking you this.)</p><p>Human!AU / Immunodeficient!Sans/Reader</p>
            </blockquote>





	This Is Gross: How To Respond When Your Children Ask You For A New Sibling

**Author's Note:**

> I really like this AU and I felt I couldn't be done with it yet.  
> Follow me on tumblr for updates on this series: acoolegg.tumblr.com

Copperplate stared up at you while she sucked milk through her straw. Century played with her ice cream, spooning at the treat half-heartedly. You noticed their quiet (almost dismal) mood, looking between the two girls curiously. “Girls? Is there, uh, something the matter?” you asked after a moment.

Century tugged at her bow, playing with her cropped black hair before responding. “Well, Mom, Copperplate and I were discussing something… You might want to sit down for this.” You nodded and put the dishes you had been washing in the sink. Then, you went over to the table and sat down. Copperplate regarded her sister carefully, her wild red hair fanning across her face. “Is Dad gonna be done with work soon?” Her no nonsense tone was actually intimidating.

You shook your head, “Your father’s been working on a project, Century. I don’t want to disturb him-”

Copperplate apparently would have no part with that. She threw her head back and screamed, “DADDY!” You jumped, looking at her with wide eyes.

You frowned when you realized what she had done, “Copperplate Gothic! You-your father is _working_ right now-you’re in trouble, little girl!” You were hoping that Sans had his headphones on. When you heard a door slam open, you knew he hadn’t. There were a few curses and you watched as your husband walked into the kitchen worriedly. You stood up when you saw that his nasal cannula was out, rushing over to him. “Sans, Jesus-”

“-Language, Mommy!”

“-lemme go get your tank for you.” He was breathing heavily, his face pale as he looked between you and your daughters. You went to walk off, but he grabbed your arm. You stopped. He didn’t want you to get the tank for some reason.

“Let’s just,” he inhaled deeply, “let’s just stay here.” He fixed his mask, which had twisted awkwardly in his hurry to get to the kitchen. His breathing had even out as he looked at his daughters. “Coppie, what happened? What’s wrong?” The youngest smiled, revealing her buck toothed grin. “You didn’t give your mom a heart attack over nothing, did you?” he asked teasingly, taking the screaming in stride.

“Nope, not at all, Daddy. Century wants to tell you and Mommy something important.” Her orange eyes sparkled with innocence. (She reminded you of her uncle quite frequently.) Sans took your hand, dragging you over to the table and sitting down. You went to walk to another chair, but he pulled you into his lap. Your daughters giggled when you stuttered and blushed. Despite the fact that you two had been married for almost eight years, he still managed to get you to blush when he did sudden cute acts like that.

Once you were all situated at the table, you squirming around on Sans’ lap to get comfortable. He moved you so that your legs went across his lap. You wrapped your arms around his neck. (Had it been six years ago, you would’ve never done that. You had only recently come to terms with the fact that, while he was sick a lot, he was still pretty strong. You had seen his strength first handedly when he had you- _no!_ You are not about to think about sex with your husband! Not in front of the children! Not again!)

Century played with her bow, adjusting it so that it puffed out perfectly. You stuck your tongue out at her when she looked at you. She stuck hers out in response, puffing her dark cheeks out with air. You grinned at her when she stopped. She cleared her throat, “Well, Mom. Dad. I assume that you want to know why Coppie and I have brought you here today.” She was going to be a business leader one day, you were positive.

“You know what happens when you assume things, C.” Century glared at her father, green eyes sparking with agitation. You leaned your head against his and sighed. Here it came. “You make an ass out of _u_ and _me_.”

Century screeched, “Dad, language! There is a child at the table!”

Copperplate originally laughed, but stopped as soon as her sister called her a child. “I’m not a child, Century! I’m a big girl, too. I’m four years old, you nerd! How dare you call me a child!” she whined.

“I’m not a nerd, you dweeb!” the older shot back. They glared daggers at each other for a few seconds, until they started laughing. “You’re a dweeb, Coppie,” Century said fondly.

“You’re a nerd, Century.” They had reconciled in thirty seconds. You looked at Sans, genuinely impressed. Typically they required some kind of intervention. “Okay.” Copperplate looked at you two firmly. “Okay, Century wants to talk to you about something important.” She looked at her sister. “Century, you may talk.”

“Babies.” You raised an eyebrow curiously. Century slammed her hand against the table, her forgotten ice cream bowl clattering. You jumped, but Sans held you firmly. “We want a new baby. A boy, preferably. We would like him to be named Carrois Gothic.” You were sputtering, but fell silent when she motioned between the two of you. “Get busy, please. You told me the baby order forms take a long time to fill out. Like…” She looked at Sans. “Dad. You said they take a whole night to fill out, and we can’t be here when you guys do it. Something about confidentiality or something.”

Copperplate clapped her hands and said happily, “Confidentiality or something!”

You looked at Sans and glared. He shrugged, though you could see the blush spreading across his face. You had never heard of ‘the baby order form.’ “Yeah. We’ll, uh,” he rubbed the back of his head embarrassedly, “We’ll see what we can do, girls.” They nodded, looking at you two with happy faces. He coughed, “Can you two, uh, go to your room? Your mom and I should talk about the, the baby order form.”

Century nodded, taking Copperplate by the hand and pulling her away from the table and towards their room. You watched as they went through the arch, then continued to stare after them. As soon as you heard the door creak shut, you turned and looked at Sans with a mix of fury and horror. “Baby order forms?”

“Look, Cheesy, Century asked where babies came from one day.” You nodded, understanding that. “And she started asking all these questions after I told her about the, the order forms. She asked if she could watch and I-well, you can’t exactly tell a six-year-old that ‘filling out the order forms’ meant ‘fucking her mom into the mattress.’” You flushed and smacked his shoulder.

“Sans! That is! Jesus.” A silence fell over you two. You leaned your head against his. He reached up to his face and took his mask off. You knew from your years together (what? Eleven years, was it?) that he wanted to look at you seriously or kiss.

“Do you want another kid?” he asked after a few moments, looking up at you. You averted your eyes, contemplating it. It wasn’t your first time mulling over the subject of a third child. You wanted another child. You knew that. But two rambunctious little girls seemed a little much, especially for Sans’ health. He had so much on his plate, and you did too! Being the on-call orthopedic doctor for the local hospital left you busy. But you had made it work with your family. And- Sans seemingly read your mind. “I’ll be fine if we have another one.”

“Not that I don’t believe you, sweetheart. I really do. But. What about the child? We already have so much on our plates already. Century’s getting ready for kindergarten and Coppie’s still in daycare. My schedule’s pretty erratic and you’ve got that project for the lab. I just don’t want to miss their life-”

“You won’t.” He sounded serious as he looked up at you. He was slowing your racing thoughts, just by sounding calm and firm. “We’ve made this work with our girls. We’ll make it work with another one.”

“Do you want another kid, Sansy?” you asked, wrapping your arms around his neck and setting your forehead against his.

He nodded. “Yeah.”

His blue eyes lit up with recognition, then he snickered. “What?” you asked, staring at him.

“I know where C got the idea from.” You tilted your head, urging him to go on. He smiled, showing his teeth and the cute little gap in the middle of them. He started laughing, “I’m gonna give her a firm talking to.” You grunted when he didn’t reveal anything. “Toriel’s been talkin’ to Undyne and Alphys about adopting a kid for a while now.” Toriel was a family friend, one that you had met through Sans and Papyrus. She was the principal of a nearby elementary school (the one Century would be attending). Her husband, Asgore, watched your kids whenever you were called in and Sans couldn’t keep an eye on them. “C must’ve heard them or something and figured that if they were getting a baby, then we should get a baby. You know how she works.”

That… definitely sounded like your Century. You covered your mouth as you giggled, before laughing loudly. “Ah, that’s my girl. And you know she told Copperplate because if Coppie wants something then she gets something.” He nodded, grinning mischievously. It caught your attention. “What’s that look for?”

Sans tilted his head towards their room. “Wanna call someone tonight, see if they can watch the kids?” You blinked, feeling a blush creep up your neck. He wasn’t going to- “‘Cause I’d like to get to work on _all those forms_ tonight.” You blushed heavily, opening and closing your mouth as you tried to form a response.

“I’m going to punch you and not feel sorry about it.”

“Oh, c’mon, Cheese!”

You crossed your arms, wiggling on his lap. “Well, we better get your tank.” It was his turn to stare at you questioningly. “Because when I’m done with you, you’ll be out of breath.”

He grinned, “I think you’ve used that line before.”

“Really? Huh. I’ve used the ‘taking your breath away’ line for sure. Are you sure about that one?” Sans nodded. You shrugged. “Welp, that is unfortunate.” When he laughed, you kissed his nose.Then you kissed his forehead. “I love you,” you mumbled into his skin.

He kissed at your neck, “I love you, too.”


End file.
